[segafor, you can ignore this]

Ian, ships have the same "signatory carrier" requirement as airlines. "Signatory carriers" are companies that have signed an agreement that if anybody on board is denied entry under the VWP, the carrier is stuck removing the person from US soil, "on the first available means of transportation to the alien’s point of departure to the United States." They also agree to check passengers for a valid passport from a WWP country, ESTA pre-approval, and that onward…

Thirded. With a N-K visa attached to your passport, you will 100% be denied entry to Azerbaijan. Even with the Armenian stamp, you might get some extra questions at Azerbaijani immigration. The other direction doesn't matter as the Armenians don't care if you've been to Azerbaijan.

There is no rental agency that allows international rentals. Furthermore, bringing your own car into Azerbaijan could face fee/taxes.

Curiously, the official Irish WWOOF website advises people that it isn't work and they don't need a work visa, and they are not aware of people being denied entry for doing it. http://www.wwoof.ie/visas Perhaps they carefully avert their eyes which is why they aren't aware of it. I think there is definitely scope to ask WWOOF.ie some carefully worded questions drawing to their attention the opposite advice of the US SD. Because "needs a work visa" almost always means "won't get it".

You definitely have not overstayed, you can only overstay by being in the US when your 90 days expire, the risk that you run is being denied entry when you try to go back to the US. If you fly back to Germany from Mexico, make sure that it is a flight that does not go via the US because that means you have to enter the US even if only for an hour or two.

In many (I believe most) countries you don't need visas for woofing, I just know the USA is an exception as they are really uptight about any "working" without appropriate visas, even for non-finacial compensation. I don't have the link anymore, but a Canadian girl was removed from a bus and denied entry at the USA border for saying she was planning to woof.

Large numbers of posters crossing borders doesn't always translate into accurate or better advice. This site used to have large numbers of posters too including those staying there and crossing borders . There is mixed opinion here about Thaivisa.com.
Although crackdown is not officially in effect , Thaivisa.com did report some cases of people being given 7 days passes to get out of country and some who already had visas being denied entry . But the details are sketchy.

From my point of view, this is more about helping the part of the family that intends to obey the law instead of advising the black sheep.

I cannot imagine that they will get any problems, they have individual visas and there's no kin liability. They might be questioned about the whereabouts if there's some database entry that they travel in a group. My guess is that nothing will happen to them. Perhaps they might be denied future Schengen visas, though.

Disclaimer: All that I wrote is just…

Besides the return to the US issue, getting into Canada could be tricky. Canadian immigration officers are quite inquisitive for anything work related. I travel there for work, frequently, under an Argentinian passport with an US green card, and while I have never been rejected, it often takes a while to get through, with one on one interviews required, and I know of workmates who have been denied entry even being US citizens with a return ticket a few days after.

To get a Transit Visa you need to enter and exit via land borders. To get the visa you need to have a visa to the country you'll be exiting to, and specify a date of entry into Turkmenistan. Once you're in Turkmenistan you "may" be able to fly out, probably by paying a hefty bribe, but I wouldn't recommend it.

If you tell the embassy where you're applying for the transit visa that you intend to enter by land and fly out you'll be denied the visa.

Unless you're a skilled worker then you're going to struggle to get a job in the UK full stop right now as a non-EU national. As eurotrash said, you will raise a few red flags which could result in additional questioning at the airport and potentially denied entry to the UK if they believe you are not a genuine tourist - which you actually aren't anyway.